JP2009057416A - Direct sublimation type ink-jet ink composition and recording method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct sublimation type ink-jet ink composition which is excellent in ejection stability and is reduced in discoloration property and a recording method using the same. <P>SOLUTION: The direct sublimation type ink-jet ink composition comprises a sublimable dye, an organic solvent, a dispersant, a surfactant and water, wherein the dispersant has a structure having a hydrophilic group comprising an ethylene oxide polymer or an ethylene oxide-propylene oxide copolymer, in which the hydrophilic group and a hydrophobic group are bonded to each other through an ether bond or an ester bond and the number of sequence of the ethylene oxide polymer or the ethylene oxide-propylene oxide copolymer of the hydrophilic group is 5-20 in total. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink composition used in a direct sublimation ink jet recording method, and more particularly to a direct sublimation ink composition for ink jet recording having excellent ejection stability and less fading.

  An ink comprising a sublimation dye, at least one dispersant for shielding the dye, and at least one solvent is directly printed on a recording medium by an ink jet recording method, and then the printed matter on the medium is sublimated by the sublimation temperature of the sublimation dye. A direct ink-jet sublimation printing method in which an image is formed on a target by heating up to this point is disclosed (for example, see Patent Document 1). At this time, a dispersant for stabilizing the sublimable dye in the ink by these methods is used. However, the dispersants described in these publications have a problem that the color becomes dull because there are many impurities and an image is formed in a colored state.

  For these known cases, recently, a transparent dispersant has been used, and a technique that can reduce dullness in color has become available. For example, it is described that an acetylene glycol surfactant, an anionic, nonionic, or polymeric surfactant is used (see, for example, Patent Documents 2 and 3).

  However, in these direct sublimation ink jet inks, the ink head is likely to be clogged unless the average particle diameter of the dye is set to 200 nm or less in order to ensure ejection stability, and in some cases, particles of 100 nm or less are also present in the ink. . However, in such a fine particle state, the solubility in the dispersant increases, and the dissolved particles are deposited on the large particles. The so-called crystal growth increases the particles, which may cause clogging of the head. Come. It is presumed that this is due to the wettability of the dispersant to the dye.

  However, even if the above problems are solved, the problem still remains as a problem peculiar to sublimation ink in that the printed matter is vaporized over time and the printing becomes thin. For this reason, in order for the sublimation dye not to fade, it is necessary to fix the dye on the fiber at the same time as printing with ink and drying by applying temperature. In order to fix it, it is a problem that cannot be solved unless it is known whether the dispersant and the dye maintain the entangled state on the fiber. There is no prior example describing a technique for fixing a dye and a dispersant on a fiber in order not to fade the color on the fiber.

The inventors examined what kind of dispersing agent the sublimable dye is bound to and easily adsorbs firmly onto the fiber. As a result, it can be seen that the adhesiveness is affected by the structure of the dispersant and the ratio of the hydrophobic group and the hydrophilic group which are the binding functional groups, and that it is possible to obtain an effective means for the problems specific to the sublimation dye. It was.
JP 2000-511954 A JP 2004-42604 A JP 2004-107647 A

  The object of the present invention is to provide a technology for ensuring ink ejection stability using a transparent dispersant in a direct sublimation ink jet ink composition, and at the same time preventing printing fading due to dye vaporization. is there.

  The above problem could be solved by the following configuration.

  1. In a direct sublimation ink jet ink composition containing a sublimation dye, an organic solvent, a dispersant, a surfactant, and water, the dispersant comprises an ethylene oxide polymer or a copolymer of ethylene oxide and propylene oxide. An array of a hydrophilic group, wherein the hydrophilic group and the hydrophobic group are bonded by an ether bond or an ester bond, and an ethylene oxide polymer of the hydrophilic group or a copolymer of ethylene oxide and propylene oxide A direct sublimation type ink composition for inkjet, having a structure having a total number of 5 or more and 20 or less.

  2. In the above 1, wherein the hydrophobic group is at least one selected from an alkyl group, an alkylene group, an arylene group, an acyl group, an amino group, and an aryl group (these groups may be further substituted). The direct sublimation ink jet ink composition described.

  3. 3. The direct sublimation ink jet ink composition as described in 1 or 2 above, wherein the dispersant is present in an amount of 30 to 70% by mass with respect to the sublimable dye.

  4). 4. The direct sublimation ink jet ink composition as described in any one of 1 to 3 above, wherein the sublimation dye is at least one selected from a disperse dye, an azoic dye, a vat dye or a cationic dye. .

  5). 5. A direct sublimation type ink jet recording method using the ink composition for direct sublimation type ink jet according to any one of items 1 to 4.

  According to the present invention, it is possible to provide a direct sublimation ink jet ink having a discharge stability and less fading of an obtained image and a recording method thereof.

  In general, many polymer dispersants are not colored, but the color deteriorates even if they are used as sublimation transfer ink, especially if they have very little impurities with an absorbance of 2.0 or less. Things will disappear.

  However, such a polymeric dispersant is wide as a selection range. Accordingly, as a result of intensive studies on what kind of dispersant should be used, it has been found that a sublimation dye having a wettability with respect to the dispersant is preferable. That is, when the sublimable dye is easily wetted with the dispersant, part of the dye is dissolved and crystal growth starts. Further, if it is difficult to wet, the dispersing agent is difficult to be adsorbed to the dye, so that a lot of bubbles are involved at the time of dispersion, and the dispersion time is delayed. It has been found that the index for determining the wettability and the wettability is the structural skeleton of the polymer dispersant.

  In particular, the hydrophilic group is composed of an ethylene oxide polymer or a copolymer of ethylene oxide and propylene oxide, and the hydrophobic group and the hydrophilic group are composed of an ether bond or an ester bond. Since the balance of force between the group and the hydrophilic group is good, it was found that the dispersant was able to balance the force against the dye particles without excess or deficiency, as described above, without being too wet or too wet. . As a result, it was found that the dye particles in the ink and the hydrophilic portion of the adsorbing dispersant did not aggregate with each other, and the dye molecules were stably present in the solution and no recrystallization occurred.

  On the other hand, no precise technique has yet been found for fading. In particular, if the dye is sublimable, it has been difficult to suppress the process of fading with time.

  Therefore, I thought as follows.

  (1) Adsorption between the dispersant and the dye acts by the intermolecular attractive force between the hydrophobic group and the dye as described above. At this time, the hydrophilic group portion of the dispersant is associated with water molecules in the ink. However, after the ink is dried, there is no associated molecule with the hydrophilic group, so it moves only freely. Therefore, we focused on the molecular chain of the hydrophilic group.

  In other words, the molecules with developed chain structure of ethylene oxide polymer or ethylene oxide / propylene oxide copolymer are surrounded so as to bind around the fiber after printing. It is thought that it will be difficult to leave, and fading will be reduced. However, it can be presumed that this chain structure also has an appropriate value of length.

  In other words, if the chain structure of the ethylene oxide polymer or ethylene oxide / propylene oxide copolymer is short from a certain amount, the entanglement will be small, and it will be easy to separate from the fiber. Therefore, it becomes difficult to get entangled with the fiber.

  (2) As a result of intensive studies, it was considered that the hydrophilic group length of the dispersant is an important property as a factor that determines the length of the hydrophilic group. That is, the structure of the hydrophilic group of the dispersant has an array of ethylene oxide polymers, or an array of copolymers of ethylene oxide and propylene oxide, an ethylene oxide polymer unit, or an ethylene oxide and propylene oxide copolymer unit. When a total of 5 or more and 20 or less are arranged, most preferably 8 or more and 16 or less are arranged, the length connecting the circumference of the fibers will wrap around the entire fiber, and the dispersion It was found that the dye adsorbed on the agent can be retained, and it serves to prevent color fading after printing.

  In FIG. 1, the image figure of the entanglement degree of the dispersing agent of this invention, a sublimation dye, and a fiber is shown.

  It is considered that the hydrophobic group portion and the sublimation dye of the dispersant of the present invention are oriented and adsorbed, and the hydrophilic group portion can be firmly fixed by being entangled with the fiber length.

  The present invention will be described in more detail.

(Dispersant)
The dispersant of the present invention has a hydrophilic group made of an ethylene oxide polymer or a copolymer of ethylene oxide and propylene oxide, and the hydrophilic group and the hydrophobic group are ether-bonded or ester-bonded. The number of sequences of ethylene oxide (EO) or ethylene oxide / propylene oxide (EO-PO) is 5 or more and 20 or less.

  In the dispersant of the present invention, the hydrophobic group is at least one hydrophobic group selected from an alkyl group, an alkylene group, an arylene group, an acyl group, an amino group, and an aryl group (these groups may be further substituted). A molecular structure composed of a substituent is preferable, and an alkyl group, an alkylene group, an acyl group, an amino group, an aryl group, and the like are more preferable. Specifically, although it changes with the polymerization degrees of an ethylene oxide polymer or an ethylene oxide-propylene oxide copolymer, groups having 5 or more carbon atoms can be exemplified.

  Specific examples preferable for the present invention are shown below.

  (1) DisperBYK187 manufactured by Big Chemie, which is made of an ether bond between an ethylene oxide polymer (hydrophilic group) and a higher fatty acid (hydrophobic group).

H— (O—CH ₂ —CH ₂ ) ₈ —O—C ₁₂ H ₂₅ (EO number: 8)
(2) DisperBYK192 made of an ester bond between an ethylene oxide polymer (hydrophilic group) and ricinoleic acid (hydrophobic group).

_{H- (O-CH 2 CH 2} ) 10 -O- (CO) - (CH 2) 7 -CH = CH-CH 2 CH (OH) -C 6 H 13 (EO number: 10)
(3) Structure example of Solspurs 41000 manufactured by Nippon Lubrizol Co., Ltd., which is an ether bond between a copolymer of ethylene oxide and propylene oxide and a hydrophobic group other than fatty acid.

_{H- (O-CH 2 -CH 2} ) 4 - (O-CH (CH 3) CH 2) 4 -O-PO (OH) -O-C 12 H 25 (EO-PO : 8)
(4) DisperBYK183 manufactured by Big Chemie, which is an ether bond between a copolymer of ethylene oxide and propylene oxide and a hydrophobic group other than fatty acid.

_{H- (O-CH 2 -CH 2} ) 7 - (O-CH (CH 3) CH 2) 4 -O- (C 6 H 4) - (CH 2) 30 CH 3 (EO-PO Number: 11)
Specific examples are not limited to the above. Specifically, the dispersing agent etc. which were described in the Example can be mentioned.

  The dispersant having the above structure may be added in an amount of about 30% to 70% by weight, more preferably about 40% to 60% by weight, based on the sublimation dye. If it is 30% by mass or less, the amount of the dispersant for the dye is small, so that the storage stability is deteriorated and precipitation occurs. On the other hand, when the content is 70% by mass or more, since the dispersant is excessively present in the ink, the ink has a high viscosity and the light emission at the ink head is deteriorated. The above dispersant is blended with a dye, an organic solvent, a surfactant, and water to prepare an ink.

  Moreover, the following can be used as a sublimable dye. In the present invention, a disperse dye is preferably used as the sublimation dye. Further, in addition to the disperse dye, an azoic dye, a vat dye, or a part of the cationic dye can be used in the present invention as long as sublimation transfer is possible in an appropriate temperature range.

(Sublimation dye)
Preferred examples of the sublimable dye include (1) C.I. I Disperse Yellow 1, 3, 4, 5, 7, 8, 31, 33, 39, 42, 54, 60, 61, 64, 83, 124; (2) C.I. I Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 31, 32, 33, 34, 35, 36, 52, 54, 55, 56, 58, 60, 72, 73, 76, 80, 84, 88, 91, 92, 93, 99, 111, 113, 135, 204, 205, 206, 207, 224, 225, 227, 239, 240; (3) C.I. I Disperse Blue 20, 26, 54, 55, 56, 58, 60, 61, 62, 64, 72, 79, 81, 85, 87, 90, 91, 92, 94, 97, 98, 99, 10. 3, 104, 105, 106, 108, 128, 148, 149, 176, 186, 187, 193, 194, 195, 197, 201, 205, 207, 211, 212, 213, 214, 215, 216, 217, Examples thereof include disperse dyes such as 218, 219, 220, 221, 222, 223, 224, 225, 226, and 227. Other examples include C.I. as a vat dye. I vat red 41 etc. are mentioned. Moreover, when using black as a sublimation dye, it is preferable to use a compound disperse dye.

  The addition amount of the dye to the ink composition is 5 to 15% by mass, more preferably 9 to 12% by mass.

(Organic solvent)
Examples of the organic solvent that can be used include polyhydric alcohols (for example, ethylene glycol, glycerin, 2-ethyl-2- (hydroxymethyl) -1,3-propanediol, tetraethylene glycol, triethylene glycol, tripropylene glycol, 1,2,4-butanetriol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, 1,6-hexanediol, 1,2-hexanediol, 1,5-pentanediol, 1,2-pentanediol, 2 , 2-dimethyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 3-methyl-1,3-butanediol, 2-methyl-1 , 3-propanediol), amines (eg , Ethanolamine, 2- (dimethylamino) ethanol, etc.), monohydric alcohols (eg, methanol, ethanol, butanol, etc.), alkyl ethers of polyhydric alcohols (eg, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl) Ether, triethylene glycol monobutyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, etc.), 2,2'-thiodiethanol, amides (for example, N, N-dimethylformamide etc.), heterocyclic rings (2-pyrrolidone etc.), acetonitrile etc. That.

(Surfactant)
As the surfactant which can be used, any of cationic, anionic, amphoteric and nonionic can be used.

  Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like.

  Examples of anionic surfactants include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acyl glutamate, alkyl ether carboxylate, acylated peptide , Alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulfate Salts, secondary higher alcohol sulfates, alkyl ether sulfates, secondary higher alcohol ethoxy sulfates, polyoxyethylene alkylphenyl ether sulfates, monoglyculates, fatty acid alkylolamide sulfates, alkyl ether phosphates Salt, alkyl phosphate ester salt and the like.

  Examples of amphoteric surfactants include carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like.

  When these surfactants are used, they can be used singly or as a mixture of two or more kinds. By adding 0.001 to 1.0% by mass with respect to the total amount of the ink, the surface of the ink can be used. The tension can be arbitrarily adjusted, which is preferable.

(Other additives)
In addition to the above-mentioned compounds, the direct sublimation ink-jet ink composition of the present invention may contain a preservative, an antifungal agent, an antioxidant, a conductivity adjusting agent, a pH adjusting agent, a viscosity adjusting agent, a surface tension, if necessary. Additives such as regulators, oxygen absorbers, and / or nozzle clogging inhibitors can be further used, and the type of such additives used can be determined as appropriate. In particular, the use of a fungicide is preferable.

  Antifungal agents that can be used in the present invention include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, and / or 1,2-dibenzisothiazoline- 3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN of ICI) and the like can be mentioned.

  The direct sublimation inkjet ink according to the present invention is used in a sublimation transfer inkjet recording method. Here, in the sublimation transfer ink jet recording method, preferably, an ink containing a sublimation dye is used to print an intermediate image on the intermediate transfer medium by the ink jet recording method, and this intermediate transfer medium is placed on the surface of the transfer object to be sublimated. Heating the intermediate transfer medium at a temperature and for a time sufficient to sublimate and attach the functional dye to the surface of the transfer object.

  In the present invention, the intermediate transfer medium is not limited as long as it can hold an intermediate image by a direct sublimation ink-jet ink composition and can be satisfactorily transferred to a transfer object, but paper is preferably used. According to a preferred embodiment of the present invention, it is preferable to use a special paper for ink-jet recording manufactured so as to have a performance suitable for the ink-jet recording method provided with an ink receiving layer and the like.

  In the present invention, the transfer object is not particularly limited as long as the heat transferable dye can be fixed, and examples thereof include cloth, metal, ceramic, plastic, ceramic, and concrete base material.

  Heating of the transfer object on which the intermediate transfer medium is placed is preferably performed at a temperature equal to or higher than the sublimation temperature of the sublimable dye. Since many of the sublimable dyes described above have a sublimation temperature at 145 to 200 ° C, the heating is preferably performed at a temperature equal to or higher than this temperature, preferably about 175 to 195 ° C. The transfer time may be appropriately determined, but is generally 10 to 300 seconds, more preferably 40 to 200 seconds.

  Examples are described below, but the parts in the sentence mean parts by mass.

Example 1
The following direct sublimation ink dispersion was blended.

Sublimation dye (C.I Disperse Yellow 54 (manufactured by Arimoto Chemical Co., Ltd.)) 18 parts Dispersant (DISPERBYK187 (manufactured by Big Chemie)) 9 parts Organic solvent (1,2-hexanediol) 12 parts Surface activity Agent (di (2-ethylhexyl) sulfosuccinic acid sodium salt (DES))
1.5 parts Ion-exchanged water 59.5 parts Ink dispersion liquid 250 ml adjusted with the above blending ratio was dispersed with a paint conditioner (manufactured by Nishikawa Seisakusho) for 15 hours. The ink dispersion was placed in a 500 ml pot, and 200 g of 0.5 mm diameter zircon beads were added and dispersed therein. After the dispersion, a diluted liquid blended in the ink dispersion at the following ratio was added to the ink dispersion 1 at a ratio of 1, and stirred again to prepare a final direct sublimation ink composition.

<Diluted solution>
Organic solvent (1,2-hexanediol) 15 parts Antifungal agent (Proxel GXL) 0.5 parts Ion exchange water 84.5 parts The dye concentration in the final direct sublimation ink composition after dilution is 9.0. Part by mass.

Examples 2-5, Comparative Examples 1-4
The direct sublimation ink-jet ink compositions of Examples 2 to 5 and Comparative Examples 1 to 4 were the same as Example 1 except that the dispersant, DisperBYK187 in Example 1 was changed to the dispersant shown in Table 1. Prepared.

(Evaluation methods)
The sublimation dye ink-jet ink composition produced as described above was stored in a high-temperature tank at 60 ° C. for 2 weeks, and various performances of the ink after storage were evaluated. Ink viscosity, surface tension, pH, and average particle size were employed as ink properties.

(1) Continuous emission property The above ink is put in an ink jet head, and the ink is continuously emitted for 90 minutes at a frequency of 18 kHz and a driving voltage of 14.8 V. The number of holes where ink droplets are missing is visually counted. did. The ink head used was a Konica Minolta # 204 head. Basically there should be no omissions.

(2) Maximum ejection speed The maximum ejection speed that is stably ejected from the head is measured with a monitor, and the maximum speed when the droplets from the nozzle are bent or stopped is obtained.

  The ink head used was a Konica Minolta # 204 head.

(3) Light resistance It was performed in accordance with JIS-L-0843 (xenon arc type).

  Using the direct sublimation ink jet ink composition, a solid image having a size of 110 mm × 140 mm was directly formed on a polyester cloth with a resolution of 340 × 540 dpi (dpi represents the number of dots per 2.54 cm).

  The printed fabric was then brought into close contact with a hot roll (temperature 195 ° C.) and held for 50 seconds for color development.

  As a color image sample, a piece of cloth cut to a size of 10 mm × 40 mm is exposed. After exposure, comparison was made every 20 hours using a gray scale for color fading (as defined in JIS-L-0804). Light resistance ranges from a minimum of 1 to a maximum of 8, but 5 or higher is acceptable.

(4) Average particle diameter It measured using Zeta-sizer by Superior.

  As is apparent from Table 1, any of the direct sublimation ink jet ink compositions using the dispersant of the present invention is excellent in ejection stability and has little color fading. On the other hand, it can be seen that the direct sublimation ink jet ink composition not using the sublimable dye dispersant of the present invention is inferior in any respect.

It is an image figure of fixation of a dispersing agent, a sublimation dye, and a fiber, and combination.

Claims (5)

In a direct sublimation ink jet ink composition containing a sublimation dye, an organic solvent, a dispersant, a surfactant, and water, the dispersant comprises an ethylene oxide polymer or a copolymer of ethylene oxide and propylene oxide. The hydrophilic group has a hydrophilic group, and the hydrophilic group and the hydrophobic group are bonded with an ether bond or an ester bond, and the ethylene oxide polymer of the hydrophilic group or the copolymer of ethylene oxide and propylene oxide A direct sublimation type ink composition for inkjet, having a structure having a total number of 5 or more and 20 or less. 2. The hydrophobic group is at least one selected from an alkyl group, an alkylene group, an arylene group, an acyl group, an amino group, and an aryl group (these groups may be further substituted). 2. A direct sublimation ink jet ink composition as described in 1. above. The direct sublimation ink jet ink composition according to claim 1, wherein the dispersant is present in an amount of 30 to 70% by mass with respect to the sublimable dye. The direct sublimation ink jet ink composition according to any one of claims 1 to 3, wherein the sublimable dye is at least one selected from a disperse dye, an azoic dye, a vat dye, or a cationic dye. object. A direct sublimation type ink jet recording method using the ink composition for direct sublimation type ink jet according to any one of claims 1 to 4.

Images